Today You Will Be Able to Divide Polynomials Through Long Division
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Name: Date: Block: Objective: Today you will be able to divide polynomials through long division. use long division to factor completely. use the Remainder Theorem to evaluate a polynomial. Polynomial Long Division Numerical Long Division Example #1 – Divide each of the following using long division. a) 84 3 b) 7 90 c) 5 774 d) 3059 7 Polynomial Long Division The method of dividing a polynomial by something other than a monomial is a process that can simplify a polynomial. Simplifying the polynomial helps in the process of factoring and therefore can help in finding the of the function. Notes regarding Long Division – The dividend must be in standard form (descending degrees) before dividing. Include the degrees not present by putting 0xn. Example #2 – Divide each of the following by the given factor. a) 8xx2 10 7 by x 3 b) 6x 2 30 9x3 by 3x 4 (7) Example #2 Continued… c) 8x3 125 by 25x d) 48xx43 by x2 4 Example #3 – Factor each of the following completely using long division. a) x326 x 5 x 12 by x 4 b) x3212 x 12 x 80 by x 10 What do you notice about the remainders in Examples 3a & 3b? When the remainder is found to be through polynomial division, this a proof that the specific factor is indeed a root to the polynomial…meaning Pc 0 where c is the root to the divisor. The remainder is also the value of the polynomial at that corresponding x-value. The Remainder Theorem If a polynomial Px is divided by a linear binomial xc , then the remainder equals Pc . NOTE – This theorem evaluates a function at a specific x-value. (8) Example #4 – Given the function P( x ) x32 7 x 4 find P( 3) using direct substitution. Then use long division to verify the value of P3. Example #5 – Find P1 given P( x ) x2 9 x 16 . Then conclude what this implies about Px at x 1. (9) Name: Date: Block: Polynomials HW #2 1. Find each quotient by using long division. 32 43 48xx 72 16 a) 5x 3 x 2 x 7 x 5 b) 2 62x c) 7x3 11 x 2 7 x 5 x 2 1 d) 3x32 12 x 12 x 48 3 x 12 2. Factor each of the following polynomials completely given a factor. a) x 5 is one factor of 2x32 x 43 x 60 b) x 5 is one factor of x326 x 3 x 10 (10) Question #2 Continued… c) x3215 x 56 x by x 7 d) 6x32 23 x 83 x 30 by x 6 3. Using the Remainder Theorem and Long Division evaluate each polynomial. Check your answers using Direct Substitution on Desmos. a) Find P5 given P( x ) x32 4 x x 2. b) Given g x 3 x32 5 x 4 , find g 2. (11) .